1. Field of the Invention
This invention has relation to built-up roof structures useful to insulate and protect relatively flat roofs.
2. Description of the Prior Art
It is known to prepare a built-up roof structure by supporting a waterproof membrane comprising a plurality of alternating layers of felt and layers of bituminuous material directly on the upper surface of a roof deck, with a thermal insulating layer of closed cell, foamed insulating members defining fissures between adjacent members to allow water to run down between these members to the membrane. A water permeable layer of loose gravel is spread over the surface of the insulating layer to complete the structure. See U.S. Pat. No. 3,411,256 granted Nov. 19, 1968, now U.S. Pat. No. Re. 31,007, reissued Aug. 10, 1982.
It is known to place a non-combustible fire resistant layer of gypsum board directly on a roof deck and then to adhere the aforementioned water impermeable membrane of alternating layers of felt and hot bituminous material or asphalt directly to the board. A layer of thermal insulation comprising closed cell, water impervious cellular insulating material is then affixed to the membrane. See U.S. Pat. No. 3,763,614, granted in October of 1973.
The prior art in relation to the present invention includes the art cited against these above-mentioned patents and as set out and discussed in the protest filed by The Celletex Corporation on Dec. 14, 1978 and in the Petition for Institution of Public Use Proceedings filed by The Celletex Corporation on Aug. 16, 1979, this art appearing in the file wrapper record of the Best reissue patent, U.S. Pat. No. Re. 31,007.
The file of now closed litigation pending in the United States District Court for the Middle District of Florida, Tampa Division, identified as The Dow Chemical Company v. The Celletex Corporation, Civil Action 77-0052, filed Jan. 24, 1977 is known to contain material pertinent to the prior art as set out in U.S. Pat. No. 3,411,256. The record of this litigation has not been examined, however, by applicant or those in privity with him.
Applicant and those in privity with him are aware of no closer prior art than that set out above; and they are aware of no prior art which anticipates the claims herein.